<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <link rel="stylesheet" href="https://unpkg.com/element-ui/lib/theme-chalk/index.css">
</head>

<body>
  <div id="app">
    <input type="text" v-model="a"></input>
    {{a}}
    <el-button type="danger">a</el-button>
  </div>

  <script src="https://unpkg.com/vue/dist/vue.js"></script>
  <script src="https://unpkg.com/element-ui/lib/index.js"></script>
  <script>
    const app = new Vue({
      el: '#app',
      data: {
        a: 'sss'
      }
    })
  </script>
</body>

</html>